There are many kinds of boxes or cartons known in the art, that are used for holding goods for storage and transportation. These known boxes are made of various materials, such as cardboard, wood, metal, and plastics. However, all of the known boxes have, respectively, various disadvantages, such as moisture immersion, high cost, or too heavy. Particularly, none of the known foldable boxes is suitable for all environmental conditions, such as sunshine or hot environment, wet or humid conditions, cold or frozen conditions, and stacking-up with heavy load. Therefore, there is a need or demand for a durable box which can be used in any kinds of environment in which a box would be used. At the same time, the box must be cost efficient or economical, easily foldable, easily transportable, reusable, light weight, moisture resistant, washable, and capable of stacking-up to bear heavy load for a relatively long period of time. The box should also be recyclable.
At present, no single box can meet all of these requirements. Most of one-piece board of foldable boxes are made of cardboard, waxed cardboard, or thin plastics because thick plastic boards cannot be easily folded. Such boxes usually utilize laminate layers or fillers to reinforce the side and end walls or corners of the box for better support, for instance, the box disclosed in U.S. Pat. No. 3,310,219 to Dlugopolski; However, the locking systems used thereon are not strong enough to hold the box panels together when the box is used in severe conditions, such as moisture, heat, heavy load. The novel locking system of the present invention, however, can meet the requirements of strong holding and quick assembly of the box even when the box is used under the severe conditions.
The normal locking system for the boxes are tab and slot engagements that are not deadly locked. For example, the inset tabs and the slots are used in U.S. Pat. No. 3,310,219 to Dlugopolski, and U.S. Pat. No. 3,708,103 to Evants. The barbed tabs are used in U.S. Pat. No. 4,463,997 to Densen, and U.S. Pat. No. 3,991,932 to Carmel et al. These locks are designed for cardboard material which is relatively soft and flexible. The locking system of Densen is a combination of the tab-slot engagement and barbed tabs. The barbed tabs must be bend over at the box corner to assure the locking of the additional tab-slot engagement. The assembly of such box is relatively slow and such locking cannot be used on boxes of thicker plastic materials. Due to moisture immersion or merely worn-out, the tab-slot engagement or barbed tabs, even the combination thereof in Densen, will be weakened.
Therefore, it is an object of the present invention to provide an improved foldable tote box that meets all requirements stated above.
It is another object of the present invention to provide a novel locking system for foldable boxes, that facilitates the quick assembly or disassembly of the box, while provides the box with enhanced strength and stability.
It is a further object of the present invention to provide a foldable tote box that may have hollow support beams at all four sides for enhancing support strength for stacking-up boxes and providing insulation and cushion functions to absorb impacts.